Conventionally, there has been developed a film-like product, which is obtained by coating a material having a hydrophobicity on a solid material (e.g., metallic materials, ceramic materials, glass materials, and resin materials), to impart functions (e.g., antifouling property and self-cleaning ability) as well as hydrophobicity to the material.
These hydrophobic materials can be used in various fields (e.g., window glass, automobile bodies, panels of solar cells, traffic signals, and playground equipment in the park) and can reduce or omit maintenance of cleaning.
Particularly, a so-called “superhydrophobicity” which means a contact angle with respect to water is 150° or more, is advantageous because it exhibits drastically improved functions described above compared to the general hydrophobicity.
It has been known that a coated film exhibiting this “superhydrophobicity” is obtained by formation methods such as sol-gel methods (see, for example, NPL 1). However, the sol-gel methods have been problematic in terms of production as described below. For example, when a formulation solution is left to stand before coating, reaction proceeds as time passes, resulting in the gelatinized solution. In addition, after coating, some reaction conditions of high temperature and long time are required.
On the other hand, there has been known the following method in order to obtain the hydrophobic coating including an acrylic resin and fine particles.
(i): a hydrophobic coating obtained by dissolving an acrylic resin in an organic solvent with fine particles mixed and incorporating ethylene glycol or polyethylene glycol thereinto (see, for example, PTL 1). In this technique, it is described that fluorine is incorporated into a main chain or a side chain of the acrylic resin.